Anti-stalling motor fuel



United States Patent 3,148,039 ANTI-STALLING MGTUR FUEL George W. Eckert, Wappingers Faiis, N.Y., assignor to Texaco Inn, New York, N.Y., a corporation of Delaware No Drawing. Filed Nov. 14, 1060, Ser. No. 68,626 9 Ciairns. (Cl. 44-71) This invention relates to a volatile gasoline composition of improved anti-stalling properties containing an adduct of an ether monocarboxylic acid and an alkyl primmy amine. More particularly it involves the discovery that adducts of aryloxy substituted aliphatic monocarbox ylic acids and alkyl primary amines are effective antistalling, anti-icing additives for gasoline.

In a commonly assigned copending application Serial No. 811,535 filed May 7, 1959, it is disclosed that adducts of hydrocarbyl monocarboxylie acids and high base strength amines of prescribed chain length are effective anti-stalling and anti-icing additives for volatile gasolines. The subject invention involves the discovery that adducts of aryloxy substituted aliphatic monocarboxylic acids and alkyl primary amines are also effective anti-stalling and anti-icing gasoline additives.

The gasoline fuel composition of this invention comprises a substantial concentration of volatile components, and 0.001 to 0.1 weight percent of an aryloxy substituted aliphatic monocarboxylic acid-primary amine adduct having the general formula: RNH :RORCOOH wherein R is an aliphatic hydrocarbyl radical containing 2 to 24 carbon atoms or a mixture thereof, R is a monocyclic or bicyclic aromatic hydrocarbyl radical containing 6 to 14 carbon atoms and R is a divalent aliphatic hydrocarbyl radical containing 1 to 7 carbon atoms. The presence of the amine-aryloxy substituted acid adducts in prescribed concentration imparts outstanding anti-icing and anti-stalling properties to volatile gasoline compositions.

When internal combustion engines are operated on a gasoline fuel having the desired volatility characteristics for cold weather driving, a stalling problem is encountered during the warm up period, particularly under cool, humid atmospheric conditions. It has been generally recognized that the cause of repeated engine stalling in cool, humid weather is the formation of ice in the carburetor. Gasoline evaporating in the carburetor has a suflicient refrigerating effect to condense and freeze moisture present in the air. Ice particles deposit on the metal surfaces of the carburetor and partially or completely block the air passage between the carburetor throat and the carburetor throttle valve with resulting stalling, particularly when the engine is idling.

The amine-aryloxy acid adducts of this invention are particularly useful in highly volatile fuels having a Reid vapor pressure above about 9 which are particularly prone to engine stalling due to ice formation under cool, humid conditions. Stated another way, the additives of the invention are particularly useful in winter gasoline employed in northern portions of the country since they have Reid vapor pressures between about 9 and 13.5, depending on the area.

The amine-aryloxy substituted monocarboxylic acid adducts employed as anti-stalling anti-icing additives in the gasoline fuels of the invention are usually solids and are simply prepared by mixing equimolar portions of a C to C aliphatic primary amine with an aryloxy substituted aliphatic monocarboxylic acid. Since the aliphatic hydrocarbyl primary amines containing 2 to 24 carbon atoms have high base strengths they readily form stable adducts with aryloxy substituted aliphatic hydrocarbyl monocarboxylic acids.

The preferred amines for forming the amine-aryloxy monocarboxylic acid adducts are mixtures of tertiary alkyl primary amines such as a mixture of t-alkyl primary amines containing 11 to 14 carbon atoms, Primene 81R, and a mixture of alkyl primary amines containing 18 to 24 carbon atoms, Primene JMT. In addition to these mixtures individual primary amines such as lauryl amine, stearyl amine, oleyl amine, n-butylamine, 2-ethyll1exylamine, isoamylamine and t-butylamine are also used in preparing amine-aryloxy substituted acid adducts.

The aryloxy substituted aliphatic monocarboxylic acids employed in preparing the adducts are represented by the formula: ROR"COOH wherein R is a monocyclic or bicyclic aromatic hydrocarbyl radical containing 6 to 14 carbon atoms and R" is a divalent aliphatic hydrocarbyl containing 1 to 7 carbon atoms and preferably 1 to 4 carbon atoms. Examples of aryloxy substituted aliphatic monocarboxylic acids used in preparing the adducts are the following: Phenoxy-acetic acid, alpha-phenoxypropionic acid, beta-phenoxy-valeric acid, Z-naphthoxyacetic acid, alpha-(1-naphthoxy)-propionic acid, beta-(Z-methyl-l-naphthoxy)-n-butyric acid, 3-methy1phenoxyacetic acid, Z-butylphenoxy acetic acid and beta-(4-methyl-1- phenoxy) caprylic acid. In the preferred aryloxy substituted aliphatic monocarboxylic acids, the aryloxy radical is a phenyl radical, a naphthyl radical or their alkyl substituted derivatives in which the alkyl radical contains 1 to 3 carbon atoms.

The amine-aryloxy monocarboxylic acid adducts effective as anti-stalling and anti-icing additives in the gasoline fuels of the invention are exemplified by the following: Lauryl amine-phenoxyacetic acid adduct, n-butylaminealpha-phenoxypropionic acid adduct, stearyl amine-betaphenoxypropionic acid adduct, oleyl amine-alpha-phenoxybutryric acid adduct, lauryl amine-Z-naphthoxyacetic acid adduct, a LC -C alkyl amine-alpha phenoxypropionic acid, a LC -C alkyl amine-alpha (2-methyll-naphthoxy) acetic acid adduct, and a t-C C alkyl amine-alpha (Z-methyl-l-phenoxy) Valerie acid adduct.

A surprising feature of this invention is the specificity of amine-aryloxy substituted aliphatic acid adducts as anti-stalling and anti-icing additives. As will be demonstrated hereafter amine adducts of other ether acids are relatively ineffective in imparting such properties to gasoline fuels. For example, the amine adducts of alkoxy substituted aliphatic monocarboxylic acids and the amine adducts of alkoxy substituted aromatic acids are relatively ineffective in imparting anti-icing and anti-stalling properties to gasoline fuels.

The amine-aryloxy substituted monocarboxylic acid adducts are effective anti-stalling, anti-icing additives in concentration of 0.001 to 0.05 weight percent of the gasoline. Adduct concentrations as high as 0.1 Weight percent can be employed but lower concentrations falling within the preferred 0.001 to 0.02 weight percent range are just as effective from the standpoint of imparting antistalling and anti-icing properties to gasoline. Concentra-' tions of the order of 4 to 16 lbs. of adduct per thousand bbls. of gasoline equivalent to concentrations of 0.0015 to 0.006 weight percent respectively have proven particularly effective in forming fuels of excellent anti-stalling properties.

The action of the adducts as anti-stalling, anti-icing additives was evaluated in carburetor icing demonstrator apparatus consisting of a single cylinder Briggs and Stratton engine equipped so that cooled, moisture-saturated air from an ice tower is drawn through a simple glass tube gasoline carburetor and fed into the engine. The gasoline sample is placed in a sample bottle and is drawn into the glass carburetor through a hypodermic needle which is usually 20 gauge. Evaporation of the gasoline in the glass tube further cools the cold, moist air with resulting ice formation on the throttle plate. The formaa ct tion of ice on the throttle plate causes the engine to stall and the time required for the engine to stall due to ice formation is recorded and serves as a measure of the icing and stalling properties of the fuel being tested. The englue is run at 3500 rpm. because this engine speed has been found to be best for differentiating between the icing and stalling properties of different fuels. Since most fuels stall in l4 minutes, 300 seconds is the maximum time for a run. A recording of 300 seconds indicates no stall within the test period. Each fuel is run four times in succession and the average is reported. If the difference between runs are great, the glass tube carburetor and test throttle are washed with alcohol and the runs repeated. A leaded winter grade premium gasoline having a Reid vapor pressure of about 13 gives a stall in about 4565 seconds in this test. Additives which raise the stalling time to over 150 seconds and preferably over 200 seconds are regarded as effective anti-stalling, anti-icing additives.

The base fuel employed to evaluate the effectiveness of amine-aryloxy monocarboxylic acid adducts as antistalling, anti-icing additives for gasoline was a winter grade premium gasoline having an octane rate of about 100 and containing 3 cc. of TEL per gallon. This winter grade gasoline, which had a 50% ASTM Distillation Point of 210 and a Reid vapor pressure of about 13 lbs., was ideally suited for testing the stalling characteristics of the additives because of its high vapor pressure. This base fuel had an average stalling time of 60 seconds in the aforedescribed stalling test.

In the above described test both amines per se and the aryloxy substituted aliphatic monocarboxylic acids per se were ineffective in improving the anti-stalling, antiicing properties of the base fuels. For example, the addition of 16 lbs. per thousand bbls. of a t-C to C alkyl primary amine (Primene 81R) and a PC -C alkyl amine (Primene IMT) to the base fuel gave products having average stalling times of 61 and 46 seconds respectively which values are essentially the same as the average stalling time of 60 seconds obtained with the base fuel. Aryloxy substituted aliphatic monocarboxylic acids are also relatively ineifective in improving the anti-stalling, anti-icing properties of the base fuel as evidenced by the fact that stalling times of 100 to 125 seconds approximately were obtained on adding similar quantities of these acids to the base fuel.

In the following table there is shown the elfectiveness of amine adducts of aryloxy substituted monocarboxylic acids as anti-stalling, anti-icing gasoline additives in comparison with the ineffectiveness of the amine adducts of other ether acids for this purpose.

Action of Amine-Acid Adduczs as Anti-icing Additives The data in the foregoing table prove conclusively the effectiveness of amine-aryloxy aliphatic monocarboxylic 4tacids as anti-stalling, anti-icing gasoline additives. The data in the above table also demonstrate the specificity of action of amine adducts of aryloxy substituted aliphatic monocarboxylic acids as anti-stalling, anti-icing gasoline additives. The presence of the amines-aryloxy substituted monocarboxylic acid adducts in the gasoline in the prescribed amounts effectively increases stalling time of the base fuel from the 60 second level to Well over the 200 second level. In contrast the amine adducts of the alkoxy substituted aliphatic monocarboxylic acids and the amine adducts of alkoxy substituted aromatic acids are relatively ineffective in improving the anti-stalling, anti-icing properties of the gasoline.

I claim:

l. A gasoline containing 0.001 to 0.1 Weight percent of an adduct of alkyl primary amine and an aryloxy aliphatic monocarboxylic acid, said adduct having the general formula: RNH :R'ORCOOH wherein R is an aliphatic hydrocarbyl radical containing 2 to 24 carbon atoms, R is selected from the group consisting of monocyclic and bicyclic aromatic hydrocarbyl radicals containing 6 to 14 carbon atoms and R is a divalent aliphatic hydrocarbyl radical containing 1 to 7 carbon atoms, said adduct imparting improved anti-stalling, anti-icing properties to said gasoline.

2. A gasoline according to claim 1 having a Reid vapor pressure above about 9.

3. A gasoline according to claim I in which said adduct is present in a concentration between 0.001 and 0.05 Weight percent.

4. A gasoline having Reid vapor pressure above about 9 and containing 0.001 to 0.05 weight percent of an adduct of an alkyl primary amine and an aryloxy aliphatic monocarboxylic acid, said adduct having the general formula: RNH :ROR"COOH wherein R is an aliphatic hydrocarbyl radical containing 2 to 24 carbon atoms, R is selected from the group consisting of monocyclic and bicyclic aromatic hydrocarbyl radicals containing 6 to 14 carbon atoms and R" is a divalent aliphatic hydrocarbyl radical containing 1 to 7 carbon atoms, said adduct imparting improved anti-stalling, anti-icing properties to said gasoline.

5. A gasoline according to claim 4 in which said adduct is a n-butylamine:Z-naphthoxyacetic acid adduct.

6. A gasoline according to claim 4 in which said adduct is a n-butylamine:alpha-phenoxypropionic acid adduct.

7. A gasoline according to claim 4 in which said adduct is a t-C to C alkyl primary amine:2-naphthoxyacetic acid adduct.

8TA gasoline according to claim 4 in which said adduct is a t-C C alkyl primary aminezalpha-phenoxypropionic acid adduct.

9. A gasoline according to claim 4 in which said adduct is a t-C C alkyl primary aminezZ-naphthoxyacetic acid adduct.

References (Zited in the file of this patent UNITED STATES PATENTS 2,688,595 Fainman Sept. 7, 1954 2,883,276 Larsen Apr. 21, 1959 2,902,353 Becker et al. Sept. 1, 1959 2,906,613 Mills Sept. 29, 1959 FOREIGN PATENTS 230,132 Australia Sept. 6, 1960 OTHER REFERENCES Petroleum Refining With Chemicals, by Kalichevsky and Kobe, 1956, Elsevier Pub. Co. page 480. 

1. A GASOLINE CONTAINING 0.001 TO 0.1 WEIGHT PERCENT OF AN ADDUCT OF ALKYL PRIMARY AMINE AND AN ARYLOXY ALIPHATIC MONOCARBOXYLIC ACID, SAID ADDUCT HAVING THE GENERAL FORMULA: RNH2:R''OR"COOH WHEREIN R IS AN ALIPHATIC HYDROCARBYL RADICAL CONTAINING 2 TO 24 CARBON ATOMS, R'' IS SELECTED FROM THE GROUP CONSISTING OF MONOCYCLIC AND BICYCLIC AROMATIC HYDROCARBYL RADICALS CONTAINING 6 TO 14 CARBON ATOMS AND R" IS A DIVALENT ALIPHATIC HYDROCARBYL RADICAL CONTAINING 1 TO 7 CARBON ATOMS, SAID ADDUCT IMPARTING IMPROVED ANTI-STALLING, ANTI-ICING PROPERTIES TO SAID GASOLINE. 